Water Pressure

[Harv]

<font color=blue>It's really hard to guess what you might have there</font color=blue>

What, Bill? You're not psychic? /w3tcompact/icons/crazy.gif

I haven't made a serious attempt to map out and identify all the parts in this system, mostly 'cuz it is working. Now that y'all have raised my curiosity, though, I think I will make this one of my next projects (even though I can't do it from the seat of the tractor). Might provide a good way to pass the time while the ground is drying out.

I'll take copious pictures and notes so's I can share if need be. Of course there's a fair-to-middlin' chance that after I've done all that, I might just figure it out on my own. /w3tcompact/icons/wink.gif

 

[GlueGuy]

MarkV

We have been living with our own well and water system now for nearly six years. When I was young, I my parent's home had it's own water system. I am very familiar with my current system, and have fairly good recollection of my parent's system. They are different from each other
in several ways, as yours is also different. However, the principles of operation for most domestic water systems are similar.

I will describe our water system, and you can use that to lead you to your own conclusions on your own system.

In our case, we have a 2-stage delivery system.

First Stage:

Our well is about 450' deep, and the well head is about 100' below the level of our house. We deliver the water from the well to a 10,000 gallon storage tank that is behind the house, and about 5' above the level of the house. The well is pumped with a 1HP submersable well pump.

Second Stage:

Because the water storage tank is too low to provide sufficient
pressure, we pressurize the system with a conventional pump between the water storage tanks and our house. This is accomplished with a little 1/2HP jet pump and pressure tank. Contrary to what you might believe, the size of the pump has nothing to do with the water pressure or volume
that you see inside the house.

The pressure is determined by the hi/low settings on your pressure pump. In our case, the low is set at 40 PSI (where the pump will come on), and the high setting is 60 PSI (where the pump will shut off). This allows the water pressure delivered to the house to vary from 40 PSI to 60 PSI, and is pretty typical.

Our pressure tank is an 80 gallon unit. Operating at a maximum of 60 PSI, we get about 1/3 of that gallonage (is that a word?) stored in the pressure tank, or a little over 25 gallons. Operating at a lower pressure would allow more gallons. Operating at a higher pressure yields few gallons. With the 25 or so gallons in the pressure tank, it takes a little over two minutes for the pressure pump to recover.

Like others in this forum, we also use a water filter. However, because our water out of the ground very clean, I only change the filter about every 6 months, and even then it's not very dirty. If your filter is clogged, it can seriously affect the water volume and pressure you see at the tap.

The volume of water that you get at the house is a combination of the pressure (40-60 PSI in our case), and the size of the pipes. Larger pipes = more volume. We see this affect pretty dramatically at our house. The south side of our house has older plumbing, with mostly 1/2" pipes. The north side of the house has a separate feed that is 1" through most of the house. Outside the house, both systems are fed with
a 2" main.

There is a dramatic difference between the flow we get on the north side versus the south side. If you calculate the cross-sectional are of 1/2" pipe versus 1" pipe you can see that 1" pipe (3.14" cross sectional area) has about 4 times the flow capacity of 1/2" pipe (0.79" cross sectional area).

So to trouble-shoot the pressure in your house, I would start at the pressure pump. Make sure you get a reasonable amount of pressure. Our system has a pressure gauge mounted directly to the pressure pump.

If you have reasonable pressure, check that the filter (if you have one) is not clogged. Replace if necessary.

If those are both up to snuff, then you will have to look at the size of the pipe, both underground, and in the house. Bigger pipes are better.

As for the pressure tanks, more is better, but more than one or two is overkill. A neighbor of our who is off the grid uses four 75 gallon pressure tanks that are all ganged together. It doesn't provide more pressue, just means the pressure pump doesn't have to cycle as much.



The GlueGuy

 

[MarkV]

Dave, thanks for the web site. Looks like good information.

GlueGuy, sounds like your system is much more involved than mine. I was encouraged to hear that your submersable pump is a 1hp at 450'. I have a 1.5 hp at 550 and was afraid that was my biggest problem. On the down side, I am sure that 1" pipe was run from the well to the house. When you figure 500'+ in the well and another 150' to the house, that makes for a long run. I don't have the information, here in the city, about the size of the pressure tank,so I will have to wait until next week to check that out. My guess is that the well driller went kind of cheap on the tank. It stands less than 3' high and 2' across. There is no way it could hold more than 20 to 40 gallons. Sounds like my pump may cycle way to much. I am glad to hear you can plumb multiple tanks together. Ours is in the crawl space, which is around 3' high, so several shorter tanks would work better in the space we have.

Thanks,
MarkV

 

[Anonymous Poster]

Re: pressure tank

mark,

you will need to check your pressure tank, if you do not have a tank that has a bladder or diaphragm in it, or the diaphragm is ruptured, the water will slowly absorb the air in the tank and your pump will cycle very frequently to try to pressurize the remaining air.

this happened to me, the pump was cycling off and on very frequently because of the lack of air to pressurize the tank. on the top of the tank is a tire valve looking thing, you can check the air pressure with a tire gauge , check the pressure with the tank full, that is the "kick-off pressure". then turn off the pump and drain the tank fully and recheck the pressure, that is the "kick-on pressure". if there is no pressure on the second reading then you have a waterlogged tank and most likely the diaphragm or bladder is ruptured and the air has been absorbed and is gone. most of the pressure tanks/ switches start with a 20 lb kick on pressure, you can adjust up from there. then you need to decide what you want as your kick off pressure usually 50-75 lbs. you can repressurize the tank with an air compressor or another tank, i have used this method myself without much problem.

if the bladder is gone then you will need to consider whether to buy a new pressure tank or tanks as the case may be, or just repressurize the tank as you need to with the air compressor. if the air pressure in the tank is ok then you may need to look at corroded water lines that may be the cause for decreased pressure.

hope this helps, and yea i have gone through the whole water in the country deal, even had my pump burn out and they burried the well and no one knew where it was, that was an adventure let me tell you fortunately it was in the summer. if you are looking for a water softener, check ou the water boss at lowes, does a great job and uses about half the salt of my old softener does twice the job, great at iron removal.

alex

 

[WillingtonPizza]

Correct me if I am wrong but with a submersible pump the tank also presurises the well. My well is 550 feet deep, I could have stopped at 300 feet but I grew up in a house with bad water pressure and reserve, I have a 2 hp Gould pump and run a 40 - 70 pressure setting. I do this because the person that installed the system said it does'nt matter how long the pump runs, it is how much the pump turns on and off. At work we have whole house filters but we use many and put them near where ever the appliance is. We also have a seperate pressure tank on the feed side of the water heater, and another one on the outfeed. Good luck!!

 

[DavidH]

Mark: Everyone has explained the operation of the pumps as well as I can. My well is 600' deep with a Gould 1.5 HP pump. The pressure tank cycles on at ~35psi and turns off at ~55 psi. The pipe from the pressure tank to the house is a 1 1/2 inch PVC pipe. Pressure is good unless the washing machine is running.

DaveH

 

[GlueGuy]

WillingtonPizza,

The well pump isn't (normally) used to pressurize the pressure tank, but it might be in a cheap system. If your well is 550' deep, I would think that would be a problem. The well pump should only need to get the water to the pressure tank, and a second pump is used to pressurize the tank. There should also be a check valve to prevent the pressurized tank from back-feeding to the well.

You're right, the size of the pump is almost immaterial. All it needs to do is pump enough water to stay ahead of the maximum draw from the pressure tank. It's the pressure in the tank that does all the work after that.

The GlueGuy

 

[GlueGuy]

MarkV,

It doesn't really matter how big the pipe is from the well to the pressure tank. Your water pressure is developed in the pressure tank, and the air bladder in the tank is what should push the water to the house.

Our 80 gallon pressure tank is about 4' high and a couple feet in diameter, so I bet yours is about 60 gallons or so.

If the pump is cycling a lot, the bladder might be ruptured, or it may have lost its pre-charge. I check the pre-charge as part of my spring-time maintenance. You normally need about the same pressure in the empty tank as the low-on setting on your pressure pump.

How many pumps are in your system? One? Two? If you only have the well pump, then you probably need the 1.5HP motor (maybe even bigger). That's a heck of a water column to lift plus pressurize the tank.

The GlueGuy

 

[DavidH]

My 600' well has the 1.5 HP pump and that's the pump that pressurizes the pressure tank. I also have a 250' well with an 1/2 HP pump that pressurizes the pressure tank. The 600' well cost me 10k to put in and I know it was done right. Now some ranches have 3000 gal. storage tanks and they require a second pump. When I can afford another 3K I plan on getting the storage tank.

DaveH

 

[GlueGuy]

Good luck on 3K for the storage tank. Our setup ran a little over $15K for the 10K gallon storage. $5K for the tank, and another $10K for various and sundry (concrete and plumbing mostly).

The GlueGuy